My company has just transitioned from an IMAP provider to a Microsoft Exchange server. As part of the transition, I moved all of my old messages from the various IMAP folders into corresponding folders on the Exchange server.
They've moved, but some of the message are showing the wrong date in the Apple Mail list views. The date is still correct in the message itself, but all of the timestamps in the list view are showing the date and time that I moved the messages, not when they were created. From some Google searches, it looks like it's the "date received" that's now wrong in the messages, and that's what the list views use.
What's weird is that it didn't do this to all of my messages - just some of them. It does look like it did it to all of the messages that were in my old IMAP "sent" folder.
How can I fix this? The messages are now in scrambled order in the list view, rather than showing in the correct (date sent/created) order - but even if I could fix the sort order, it's annoying that the timestamp has been replaced with the time it was moved into the Exchange server. I want the "received date" to go back to the date it was actually received, or if that's now impossible, I'd like to set it to the same timestamp that's in the message itself. Or, worst case, if I need to just restore all my messages from a Time Machine backup, how do I prevent this from happening the next time I try to copy these to the Exchange server?